| 摘要 |
PURPOSE:To enable a simple circuit to detect a zero adjustment being impossible and also to remove a bad influence on a system at that time by applying a carry or backward-carry output from an up-down counter to a clock pulse generator together with a zero adjustment command. CONSTITUTION:Assuming that while control input S to clock pulse generator 4 generates a clock pulse at level H, zero adjustment command A operates at level H, up-down counter 5 is reset by set pulse RS under command A when a zero adjustment becomes impossible with Vout greater than (e<->) regardless of a value of (e0), and consequently it starts counting up through the operation of a servo system. Right before output Dout of counter 5 overflows, carry output B is sent out and the level turns into L to put output S of AND8 in level L for the cutting-off of clock pulse C, thereby holding this state until a next zero adjustment command arrives. Therefore, the zero adjustment is detected being impossible and a bad influence upon the system in this case can be evaded. |
